Modernize core apps
Meta issue, details should probably be discussed in separate issues.
We have a number of candidate replacement apps for some of the crustier core apps. It'd be good to finally land at least some of them this cycle, so we should figure out what's missing for each of them and try to get it done early in the cycle.
- g-t -> kgx (but maybe rename kgx to something generic first?)
- cheese -> camera
- gedit -> g-t-e
- new image viewer?
- new video player?